One advantageous application of the invention is the use of the cam follower roller device in a fuel injection pump intended for an internal combustion engine, notably of a motor vehicle.
As is known per se, a device such as this comprises a tappet and a roller mounted to rotate on the tappet and designed to collaborate with a cam synchronized with the internal combustion engine camshaft so that the rotation of the camshaft leads to a periodic displacement of a piston of the pump that rests against the said tappet, to allow fuel to be delivered.
Another advantageous application of the invention is the use of the device in a rocker system designed for controlling the valves of an internal combustion piston engine.
In this application, the roller of the device is designed to collaborate, by rolling on it, with a cam of the engine camshaft so that rotation of the camshaft causes a periodic pivoting of a rocker element, to open and close the valves of the engine.
Conventionally, the tappet of such devices is made of a relatively solid single piece, for example by cold forging. The tappet therefore has relatively high inertia, and this may lead to energy losses during operation.
Furthermore, the roller of the device is generally mounted to rotate on the tappet via an attached spindle.
Now, this spindle is conventionally mounted on the tappet by upsetting or crimping, and this can cause the said tappet to become deformed.
When this happens, it is possible that the tappet manufacturing tolerances are no longer met, and this proves problematical in obtaining correct sliding of the tappet inside the guide bore formed in the associated housing.
It is an object of the present invention to address these disadvantages.
More specifically, it is an object of the present invention to provide a cam follower roller device that has relatively low inertia, that is reliable, that is economical, and that is easy to manufacture and to assemble.